The subject of the present invention is a device acting as a tell-tale of an attempt to break into an opening panel, it being possible for such an opening panel to be a door to a building or to a house, installed on the outside or on the inside, a shutter with one or more swing leaves, a door or lid to an item of furniture such as a chest.
One of the ways commonly used for breaking into a building, a house or into premises in particular, or for forcing a chest consists in engaging a penetrating tool such as a crowbar or a cold chisel between the door and its surround so as to reach the lock bolt of the lock or the ratch or the hinges of the door.
Several solutions have already been proposed for detecting such attempted break-ins.
In particular, international patent application WO-A-99/38134 describes a burglar-proof device which comprises an elongate tubular element which is fixed securely to the exterior face of the surround of an opening panel and which, on the same side as the slot separating the surround from the door, has a deformable wall which can act on an electric displacement sensor.
Other known burglar-proof devices are designed to be installed in the space between the opening panel and its surround. This is the case in particular of the burglar-proof device described in European patent application EP-A-0 208 876, which comprises two longitudinal fixed parts distant from one another and the space between which is obstructed by a longitudinal blade which pivots against the action of a spring when acted upon by a forcing tool.
The object of the present invention is to propose a burglar-proof device which is simpler and more effective than those currently known.
The burglar-proof device according to the invention can be fixed to a surface of a receiving wall situated in or in the vicinity of at least part of the periphery of an opening panel such as a door or a shutter.
According to the invention, this device comprises an elongate tubular element having a bearing wall bearing against said receiving surface, at least one fastening member which passes through a passage formed in said bearing wall of the elongate element and which is fastened to said receiving wall, at least one elastic return member placed in said elongate element and interposed between said fastening member and said bearing wall of this elongate element, and at least one displacement sensor installed in said elongate element and collaborating with said receiving wall, so that when said elongate element is urged against the action of said elastic member and moves away from said receiving wall, said displacement sensor is able to deliver an electric signal.
According to a preferred alternative form of the invention, said elastic member comprises two opposed branches the central part of which cooperates with said fastening member and the end parts of which bear against said bearing wall of the elongate element.
According to an alternative form of the invention, said fastening member comprises a spacer bearing against said receiving wall and comprising wings for holding said elastic member and a central passage for the passage of a fastening element such as a screw.
According to another alternative form of the invention, said fastening member comprises a spacer bearing against said receiving wall and having a central passage for the passage of a fastening element such as a screw, said elastic member being sandwiched between this spacer and the head of this fastening element.
According to the invention, said spacer may advantageously comprise an inclined ramp along which said elongate element can rise when urged laterally.
According to a preferred alternative form of the invention, said elongate element comprises a first section piece in the shape of a U, the base of which constitutes said bearing wall and a second section piece in the shape of a U which envelopes and covers said first section piece and which clips onto said first section piece.
According to an additional alternative form of the invention, said elongate element carries a plate designed to stretch forward from the actuating member of a means of locking the opening panel, this plate having an opening for the passage of a key which can be introduced into this actuating member.
According to an alternative form of the invention, a displacement sensor is inserted between said plate and the surface of the opening panel.
According to the invention, said displacement sensor preferably consists of a switch.
According to the invention, the body of said switch may also be subjected to a spring acting toward said receiving wall.
According to the invention, the device is preferably installed against a surface of the door.
According to an alternative form of the invention, the device could be installed against a surface of the door surround.